A Digital Subscriber Line Access Multiplexer (DSLAM) is a network device that provides a broadband connection to one or more customers over a plurality of respective subscriber lines. The DSLAM is connected toward the customer via a plurality of subscriber lines to Customer Premise Equipment (CPE) and is connected toward the network via at least one high-speed connection. The modulation format used by a DSLAM for communication over subscriber lines may be, for example, Asymmetric Digital subscriber Line (ADSL), Very-high-bitrate Digital Subscriber Line (VDSL), Symmetric-high-bitrate Digital Subscriber Line (SHDSL), or other known DSL modulation formats.
During operation, the DSLAM receives multiple signals from the plurality of subscriber lines and multiplexes the signals for transmission toward the network over the high-speed connection. The DSLAM also receives a high-speed data stream from the network and demultiplexes the high-speed data stream for transmission across the plurality of subscriber lines. In this regard, each packet received from the high-speed connection includes header information comprising a destination address or other identifier that indicates on which subscriber line the packet is to be transmitted.
Oftentimes, a subscriber's CPE may be connected to more than one subscriber line. In such a scenario, the subscriber lines extending to the same customer premises (CP) may be bonded to form a high-speed data channel having an aggregated data rate that is greater than the data rate of any single one of the subscriber lines. When a packet destined for such CP is received by the DSLAM, the packet is fragmented into a plurality of fragments. The fragments are then transmitted across the subscriber lines such that each fragment is carried by a single respective subscriber line, and the plurality of fragments are recombined at the CPE to form the original data packet fragmented at the DSLAM. The process of fragmenting packets of a data stream for transmission over a plurality of subscriber lines and then recombining the fragments after transmission is referred to as “bonding.” Bonding allows for faster delivery of a stream of data packets than is otherwise possible with a single subscriber line.